Write your poetry, and then rewrite it. Never send your poetry off as soon as you have written it, as editors can usually tell when this is the case.
Search for creative writing websites online. Use a search engine to search for online journals, or use a specialized search engine. Duotrope's Digest is a website that searches through online journals in parameters set by you. For instance, you can search only for websites that pay.
Send your poetry to some websites that do not pay. Most paying websites will not even look at your work unless your biography contains a track record of being published, online or in print.
Send your poetry to websites that do pay, after you have built an impressive body of published work. Be sure to send previously unpublished poetry to the new journals, and send as many as they will allow.